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2023 N A T I O N A L C O O P E R A T I V E H I G H W A Y R E S E A R C H P R O G R A M NCHRP RESEARCH REPORT 1066 Risk Assessment Techniques for Transportation Asset Management CONDUCT OF RESEARCH Shobna Varma StarIsis Corporation Lewis Center, OH Caroline Dickey Charles Pilson Mott MacDonald Raleigh, NC Gordon Proctor Gordon Proctor & Associates, Inc. Dublin, OH Cassandra Bhat Amanda Vargo Brenda Dix ICF Washington, DC Subscriber Categories Highways â¢ Administration and Management â¢ Planning and Forecasting Research sponsored by the American Association of State Highway and Transportation Ofcials in cooperation with the Federal Highway Administration
NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM Systematic, well-designed, and implementable research is the most effective way to solve many problems facing state departments of transportation (DOTs) administrators and engineers. Often, highway problems are of local or regional interest and can best be studied by state DOTs individually or in cooperation with their state universities and others. However, the accelerating growth of highway transporta- tion results in increasingly complex problems of wide interest to high- way authorities. These problems are best studied through a coordinated program of cooperative research. Recognizing this need, the leadership of the American Association of State Highway and Transportation Officials (AASHTO) in 1962 ini- tiated an objective national highway research program using modern scientific techniquesâthe National Cooperative Highway Research Program (NCHRP). NCHRP is supported on a continuing basis by funds from participating member states of AASHTO and receives the full cooperation and support of the Federal Highway Administration (FHWA), United States Department of Transportation, under Agree- ment No. 693JJ31950003. The Transportation Research Board (TRB) of the National Academies of Sciences, Engineering, and Medicine was requested by AASHTO to administer the research program because of TRBâs recognized objectivity and understanding of modern research practices. TRB is uniquely suited for this purpose for many reasons: TRB maintains an extensive com- mittee structure from which authorities on any highway transportation subject may be drawn; TRB possesses avenues of communications and cooperation with federal, state, and local governmental agencies, univer- sities, and industry; TRBâs relationship to the National Academies is an insurance of objectivity; and TRB maintains a full-time staff of special- ists in highway transportation matters to bring the findings of research directly to those in a position to use them. The program is developed on the basis of research needs iden- tified by chief administrators and other staff of the highway and transportation departments, by committees of AASHTO, and by the FHWA. Topics of the highest merit are selected by the AASHTO Special Committee on Research and Innovation (R&I), and each year R&Iâs recommendations are proposed to the AASHTO Board of Direc- tors and the National Academies. Research projects to address these topics are defined by NCHRP, and qualified research agencies are selected from submitted proposals. Administration and surveillance of research contracts are the responsibilities of the National Academies and TRB. The needs for highway research are many, and NCHRP can make significant contributions to solving highway transportation problems of mutual concern to many responsible groups. The program, however, is intended to complement, rather than to substitute for or duplicate, other highway research programs. Published research reports of the NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM are available from Transportation Research Board Business Office 500 Fifth Street, NW Washington, DC 20001 and can be ordered through the Internet by going to https://www.mytrb.org/MyTRB/Store/default.aspx Printed in the United States of America NCHRP RESEARCH REPORT 1066 Project 08-118 ISSN 2572-3766 (Print) ISSN 2572-3774 (Online) ISBN 978-0-309-70913-2 Library of Congress Control Number 2023946701 Â© 2023 by the National Academy of Sciences. National Academies of Sciences, Engineering, and Medicine and the graphical logo are trade- marks of the National Academy of Sciences. All rights reserved. COPYRIGHT INFORMATION Authors herein are responsible for the authenticity of their materials and for obtaining written permissions from publishers or persons who own the copyright to any previously published or copyrighted material used herein. Cooperative Research Programs (CRP) grants permission to reproduce material in this publication for classroom and not-for-profit purposes. Permission is given with the understanding that none of the material will be used to imply TRB, AASHTO, APTA, FAA, FHWA, FTA, GHSA, or NHTSA endorsement of a particular product, method, or practice. It is expected that those reproducing the material in this document for educational and not-for-profit uses will give appropriate acknowledgment of the source of any reprinted or reproduced material. For other uses of the material, request permission from CRP. Cover photos: At top left: iStock.com/mrolands At top right: iStock.com/filadendron At bottom left: Bigstock.com/iqoncept At bottom right: iStock.com/PeterHermesFurian NOTICE The research report was reviewed by the technical panel and accepted for publication according to procedures established and overseen by the Transportation Research Board and approved by the National Academies of Sciences, Engineering, and Medicine. The opinions and conclusions expressed or implied in this report are those of the researchers who performed the research and are not necessarily those of the Transportation Research Board; the National Academies of Sciences, Engineering, and Medicine; the FHWA; or the program sponsors. The Transportation Research Board does not develop, issue, or publish standards or spec- ifications. The Transportation Research Board manages applied research projects which provide the scientific foundation that may be used by Transportation Research Board sponsors, industry associations, or other organizations as the basis for revised practices, procedures, or specifications. The Transportation Research Board; the National Academies of Sciences, Engineering, and Medicine; and the sponsors of the National Cooperative Highway Research Program do not endorse products or manufacturers. Trade or manufacturersâ names or logos appear herein solely because they are considered essential to the object of the report.
e National Academy of Sciences was established in 1863 by an Act of Congress, signed by President Lincoln, as a private, non- governmental institution to advise the nation on issues related to science and technology. Members are elected by their peers for outstanding contributions to research. Dr. Marcia McNutt is president. e National Academy of Engineering was established in 1964 under the charter of the National Academy of Sciences to bring the practices of engineering to advising the nation. Members are elected by their peers for extraordinary contributions to engineering. Dr. John L. Anderson is president. e National Academy of Medicine (formerly the Institute of Medicine) was established in 1970 under the charter of the National Academy of Sciences to advise the nation on medical and health issues. Members are elected by their peers for distinguished contributions to medicine and health. Dr. Victor J. Dzau is president. e three Academies work together as the National Academies of Sciences, Engineering, and Medicine to provide independent, objective analysis and advice to the nation and conduct other activities to solve complex problems and inform public policy decisions. e National Academies also encourage education and research, recognize outstanding contributions to knowledge, and increase public understanding in matters of science, engineering, and medicine. Learn more about the National Academies of Sciences, Engineering, and Medicine at www.nationalacademies.org. e Transportation Research Board is one of seven major programs of the National Academies of Sciences, Engineering, and Medicine. e mission of the Transportation Research Board is to provide leadership in transportation improvements and innovation through trusted, timely, impartial, and evidence-based information exchange, research, and advice regarding all modes of transportation. e Boardâs varied activities annually engage about 8,000 engineers, scientists, and other transportation researchers and practitioners from the public and private sectors and academia, all of whom contribute their expertise in the public interest. e program is supported by state transportation departments, federal agencies including the component administrations of the U.S. Department of Transportation, and other organizations and individuals interested in the development of transportation. Learn more about the Transportation Research Board at www.TRB.org.
C O O P E R A T I V E R E S E A R C H P R O G R A M S CRP STAFF FOR NCHRP RESEARCH REPORT 1066 Waseem Dekelbab, Deputy Director, Cooperative Research Programs, and Manager, National Cooperative Highway Research Program Jennifer L. Weeks, Senior Program Officer Anthony P. Avery, Senior Program Assistant Natalie Barnes, Director of Publications Heather DiAngelis, Associate Director of Publications NCHRP PROJECT 08-118 PANEL Field of Transportation PlanningâArea of Planning Methods and Processes John Patrick OâHar, Gannett Fleming, Inc., New York, NY (Chair) Imad Aleithawe, Waggoner Engineering, Madison, MS Majed N. Al-Ghandour, North Carolina Department of Transportation, Raleigh, NC Anne-Marie H. McDonnell, Connecticut Department of Transportation, Newington, CT Shannon McGrath, WSB, Golden Valley, MN Ehsan Nick Minaie, Fairfax, VA Alicia N. Pitlik, Cook County Department of Transportation and Highways, Chicago, IL Hamid R. Sadraie, California Department of Transportation (CALTRANS), Oakland, CA Robert Kafalenos, FHWA Liaison Matthew H. Hardy, AASHTO Liaison
AUTHOR ACKNOWLEDGMENTS The research reported herein was performed under NCHRP Project 08-118 by StarIsis Corporation. StarIsis Corporation was the prime contractor for this work. Ms. Shobna Varma, President, StarIsis Corporation, was the Project Director and Principal Investigator. The other authors of this report were Caroline Dickey and Dr. Charles Pilson from Mott MacDonald; Cassandra Bhat, Amanda Vargo, and Brenda Dix from ICF; and Gordon Proctor from Gordon Proctor & Associates. The work was done under the general supervision of Shobna Varma from StarIsis Corporation. Significant research was done in the first phase of this project. This phase included a survey of 22Â state departments of transportation (DOTs) to capture the state of the practice in assessing risks to managing trans- portation assets. Subject matter experts from several state DOTs participated in the surveys and follow-up interviews and contributed to the state of the practice on tools and techniques for risk-based asset man- agement. The project team acknowledges subject matter experts from several state DOTsâNew Jersey, Louisiana, Rhode Island, Utah, South Carolina, Maryland, New York, Colorado, Mississippi, Minnesota, Montana, Washington, Massachusetts, Tennessee, Oregon, Vermont, and Arizonaâfor participating in the survey and contributing to this effort. In the second phase of the project, techniques and guidance relating to these techniques were developed for evaluating risks to the condition and performance of transportation assets. Seven of these techniques were piloted in six state DOTs, and the results were used to update the techniques and guidance. Five additional techniques were developed using data provided by various transportation agencies. The project team acknowledges the following agency leaders and subject matter experts for contribut- ing data or being involved in the piloting of the risk assessment techniques: Kevin Marshia, Director, Asset Management Bureau, and Ken Valentine, Senior Manager, the Vermont Agency of Transportation; Chris Lupe, Senior Fiscal Analyst, the Vermont Joint Fiscal Office; Chad Allan, Seattle DOT (formerly of the Vermont Agency of Transportation); Ed Lewis, Engineering Data Manager, Kansas DOT; Maureen Kelley, Chief of Environmental and Administrative Support, and Jim Pappas and Stephanie Johnson, Director and Assistant Director of the Division of Transportation Resiliency and Sustainability, respectively, Delaware DOT; and Jim Poorbaugh, Asset Management Engineer, Mississippi DOT (formerly of the Idaho Trans- portation Department). Each person acknowledged contributed significantly to this project and to the development of risk assessment techniques and related guidance. The project team also acknowledges the contributions of Matthew Lauffer of the North Carolina DOT; Candido Camacho of the Puerto Rico Highway Authority; Gehan Elsayed of the West Virginia Division of Highways; Clint Blackburn of the City of Durham, North Carolina; Jeffrey Meek of the Minnesota DOT; Shannon McGrath (formerly of the Minnesota DOT); and Annelin Niles and Zachary Rable of the Michigan DOT.
NCHRP Research Report 1066 provides transportation asset management staff with a primer on the mathematical and statistical concepts underlying quantitative risk assess- ment; case study applications; and a set of tools and techniques for identifying and evaluat- ing enterprise-, network-, and program-level asset-management-related risks. The report and its appendices build on the AASHTO Guide for Enterprise Risk Management to provide users with practical tools and guidance on implementing them and will be of immediate interest to departments of transportation (DOTs) seeking comprehensive and easily imple- mentable strategies and tools to improve the condition and performance of transportation assets at the national, state, and local levels. Title 23 CFR Part 515 requires state DOTs to develop risk-based transportation asset management plans. To meet that responsibility, transportation agencies have relied on a limited set of methods for defining and managing risk, often using qualitative assessments, which must be executed by a subject matter expert. Under NCHRP Project 08-118, StarIsis Corporation was tasked with researching the state of practice of risk-based asset manage- ment, as well as trends and factors affecting it. The research builds on the foundation pro- vided by the AASHTO Guide for Enterprise Risk Management, providing specific assistance in the selection and application of several quantitative risk management tools and tech- niques identified through the research. NCHRP Research Report 1066 documents and summarizes the conduct of research for NCHRP Project 08-118. Twelve appendices are provided in an associated publication, NCHRP Web-Only Document 366: Risk Assessment Techniques for Transportation Asset Management: Appendices, which can be accessed on the National Academies Press website (nap.nationalacademies.org). The appendices consist of a literature review, the primer on risk-based asset management, a state of the practice summary, an assessment of constraints on implementing asset risk management, and eight pilot study applications of specific risk management approaches for different asset management cases. F O R E W O R D By Jennifer L. Weeks Staff Officer Transportation Research Board
1 Section 1 Overview of the Research 4 Section 2 Research Objectives 5 Section 3 Research Approach 5 3.1 Phase I Efforts 7 3.2 Phase II Efforts 9 Section 4 Summary of Risk Management Primer 9 4.1 Glossary of Terms and Refresher of Concepts 10 4.2 Probabilities and Utilities 11 4.3 Risk Tolerance and Translating Policies into Values 11 4.4 Attitudes of Tolerance 12 4.5 Proxy Indicators 12 4.6 Decision Tree and Monte Carlo Simulation 13 Section 5 Summary of State of the Practice 13 5.1 Survey and Interview Summaries 14 5.2 Risk Management Practices in the 2019 TAMPs 15 5.3 Risk Management Practices for Managing Climate, Weather, and Environmental Risks 16 5.4 State of the Practice for Incorporating Risk Analysis into Management Systems 19 5.5 Identification of At-Risk Assets and Asset Groups 21 5.6 Practices for Incorporating Financial Risk 22 5.7 Conclusions from State of the Practice Review 24 Section 6 Selection of Tools and Methodologies 24 6.1 Off-the-Shelf Tools 24 6.2 Bridge and Pavement Management Systems 24 6.3 Linking Climate Threat Assessment and Risk Management 24 6.4 Integrating Risk Management in All Asset Management Functions 26 Section 7 Summary of Constraints to Implementation 26 7.1 General Constraints 26 7.2 Constraints to Managing Climate Change Risks 27 7.3 Constraints to Use of Management Systems in Managing Asset Risks 28 Section 8 Approach Followed for Study Selection and Testing 28 8.1 General Approaches for Forecasting Asset Management Variables 29 8.2 Use of Management Systems to Forecast Asset Risks 31 8.3 Tactics for Climate Change Risk and Resilience 31 8.4 Institutional Strategies for Enhanced Risk Assessment 31 8.5 Off-the-Shelf Tools to Demonstrate Typical Risk Assessments C O N T E N T S
31 8.6 Study Protocols 32 8.7 Tools and Techniques Selected for Study 33 8.8 Studies Selected for Detailed Protocols and Pilot Testing 33 8.9 Studies That Were Not Piloted, but for Which Detailed Protocols WereÂ Developed 33 8.10 How the Protocols and Studies Satisfy the Project Objectives 35 Section 9 Pilot Testing and Results 35 9.1 Study 1 and Study 2: Using Deterministic and Probabilistic Tools toÂ Forecast Key Asset Management Variables at a DOT 64 9.2 Study 3: Asset-Level Risk IndexâBridge Risk Utility Index 71 9.3 Study 4: Asset-Level Risk IndexâPavement Section Flooding 80 9.4 Study 7: Program-Level RiskâPavement Network Analysis 86 9.5 Study 9: Crosswalk Between Climate Change Vulnerability and Risk Terminologies 93 9.6 Study 11: Institutionalizing Risk Management into Asset Management Plans 107 Section 10 Protocols Developed for Studies That Were NotÂ Piloted 107 10.1 Study 5: Asset-Level Risk IndexâNon-NBIS Culverts 111 10.2 Study 6: Asset-Level Risk IndexâLandslide Hazard Management 115 10.3 Study 8: Program-Level RiskâBridge Network Analysis 119 10.4 Study 10: Decision Tree for Selecting Climate Risk Management Strategies 124 10.5 Study 12: Probabilistic Decision Tree for Risk Assessment 134 Section 11 Conclusions and Benefits 134 11.1 Studies 1 and 2: Deterministic and Probabilistic Forecasts 135 11.2 Studies 3, 4, 5, and 6: Asset-Level Risk Indexes 136 11.3 Studies 7 and 8: Program-Level Risk Analyses 138 11.4 Study 9: Crosswalk Between Climate Change Vulnerability andÂ RiskÂ Terminologies 138 11.5 Study 10: Decision Tree for Selecting Climate Risk Management Strategies 138 11.6 Study 11: Institutionalizing Risk Management into Asset ManagementÂ Plans 139 11.7 Study 12: Probabilistic Decision Tree for Risk Assessment 140 Section 12 Suggestions from This Research 141 Section 13 Implementation Plan 142 References 145 Appendices Note: Photographs, figures, and tables in this report may have been converted from color to grayscale for printing. The electronic version of the report (posted on the web at nap.nationalacademies.org) retains the color versions.